WATCH: Barbara Bush laid to rest in Houston

HOUSTON — Four former presidents joined ambassadors, sports stars and hundreds of other mourners on a gray, rainy Saturday at the private funeral for former first lady Barbara Bush, filling the nation’s largest Episcopal church a day after more than 6,000 people paid their respects to the woman known by many as “America’s matriarch.”

Watch funeral services for former first lady Barbara Bush in the player above.

Former President George H.W. Bush was helped into the cavernous sanctuary with a wheelchair behind his sons, former President George W. Bush and former Florida Gov. Jeb Bush, and other Bush relatives to remember his wife of 73 years. Barbara Bush died at their home in Houston on Tuesday at age 92.

Seated near the front of the church, in the same pew, were two other former presidents — Bill Clinton and Barack Obama — along with their wives and current first lady Melania Trump.

Flags were flown at half-mast for the wife of the nation’s 41st president and mother of the nation’s 43rd as the service began at St. Martin’s Episcopal Church in Houston, as the choir sang “My Country Tis of Thee.” The church is adorned with sprays of yellow garden roses, yellow snap dragons, antique hydrangeas and other flowers.

Among the other roughly 1,500 guests were former Rep. Gabby Giffords and her husband, retired astronaut Mark Kelly, and professional golfer Phil Mickelson, along with Karl Rove, and other former White House staff. Many were seen embracing in the church before the service.

President Donald Trump isn’t attending to avoid security disruptions and “out of respect for the Bush family and friends attending the service,” according to the White House. He released a statement Saturday saying his “thoughts and prayers” are “with the entire Bush family.”

A burial will follow at the Bush Library at Texas A&M University, about 100 miles (161 kilometers) northwest of Houston. The burial site is in a gated plot surrounded by trees and near a creek where the couple’s 3-year-old daughter, Robin, who died of leukemia in 1953, is buried.

The family has said Barbara Bush had selected son Jeb Bush, the former Florida governor, to deliver a eulogy along with her longtime friend Susan Baker, wife of former Secretary of State James A. Baker III, and historian Jon Meacham, who wrote a 2015 biography of her husband.

The funeral program shows that her grandchildren will also play prominent roles: her granddaughters will offer readings during the service and her grandsons will serve pallbearers.

On Friday, a total of 6,231 people stopped by the church to pay their respects. Many of the women wore the former first lady’s favorite color, blue, and trademark pearls.

After seeing how many people had lined up to pay their respects to his wife, former President George H.W. Bush decided to attend — he sat at the front of the church in a wheelchair, offering his hand and smiled as people shook it, for about 15 minutes.

Barbara and George Bush were married longer than any other presidential couple when she died Tuesday at their home in Houston. She was 92.

One of just two first ladies to have a child elected president, Barbara Bush was widely admired for her plainspoken style and her advocacy for causes including literacy and AIDS awareness.

Barbara Bush was known as the “Enforcer” in her family, the glue who kept the high-powered clan together. Eight of her grandsons will serve as pallbearers.

Some 1,500 guests are expected Saturday at a private funeral for Barbara Bush at the nation’s largest Episcopal church.

Funeral services for former first lady Barbara Bush are scheduled to begin at 12 p.m. ET. Watch live in the player above.

First lady Melania Trump, former President Bill Clinton and his wife, Hillary, and former President Barack Obama and his wife, Michelle, are among those expected to attend the by-invitation-only service at St. Martin’s Episcopal Church in Houston. Burial will follow at the Bush Library at Texas A&M University, about 100 miles (161 kilometers) northwest of Houston.

The burial site is in a gated plot surrounded by trees and near a creek where the couple’s 3-year-old daughter, Robin, who died of leukemia in 1953, is buried.

In a statement released Friday, the family said Barbara Bush had selected son Jeb Bush, the former Florida governor, to deliver a eulogy along with her longtime friend Susan Baker, wife of former Secretary of State James A. Baker III, and historian Jon Meacham, who wrote a 2015 biography of her husband.

Thousands of people on Friday paid respects to Barbara Bush, wife of the nation’s 41st president and mother of the nation’s 43rd. Bush died Tuesday at her Houston home. She was 92.